1. Field of the Invention
The present invention relates to a treatment method for green woods and an apparatus thereof, to which necessary natures as industrial lumber are given.
2. Description of the Prior Art
In general, lumbers are obtained by cutting down woods as a living thing and sawing them, and in case of using them as the lumber for building use, they exhibit the superior properties such as keeping a room environment comfortable and increasing the durability of the building by absorbing and discharging moisture depending on the temperature and humidity of the lumbers themselves. These properties are obtained by making use of the nature of woods as living thing appropriately. However, since the lumbers are living, the defects such as distortion and cracking (hereinafter referred as "distortion") after sawing are unavoidable, in case of considering as lumber for industrial use, there is a difficulty for handling those from the viewpoint of the quality stability.
Hence, a process has been conventionally indispensable, wherein after subjecting green woods to seasoning for a long period of time and at the time, when the woods are no longer distorted, sawing is carried out. However, depending on the kind of the woods and places located, the distortion has never sat down even after subjecting to long years seasoning, accordingly there are actually many kinds of woods which are recognized as not suitable for the lumber for building use (actually little woods are suitable for lumber for building use). Accordingly, a specific kind of wood is prized highly for lumber for building use, which invites not only high prices but also the destruction of the natural ecosystem by replacing a certain kind of copsewood with the specific kind of woods. Further, in a wood, which comprises portions of woods easily distorted and portions of woods little distorted, and the portions to be able to be used as lumber for building use are naturally limited, so that the area of forest to be cut down is large to obtain a given amount of lumbers, which may be an invitation to environmental destruction.
In addition, even in an appropriate wood for lumber for building use, the period of time necessary for seasoning, to which woods are subjected after cutting down, depends variously on the kinds of wood, and some of those woods necessitate ten years. During such term, the cost of hands for management and land required therefor becomes very expensive, in addition a stable supply to the market corresponding to the demand is quite difficult, which leads to a further increase in cost. Therefore, for the purpose of changing the nature of woods which are usable as lumber for building use to a wood which is used therefor as soon as possible, a method for adding an artificial treatment to a wood has been considered in a conventional art.
For example, the wood is laid in a treatment chamber, and subjected to a hot air for a given period of time to dry the conduits unreversely and change the nature of the tissue of the wood has been carried out, so that any generation of such as ex post facto cracking or bending has been prevented. In the case where a pine tree is treated in this treatment, a great amount of turpentine is discharged in melted manner and the remaining turpentine can be changed to such nature as low in viscosity, which causes to increase the workability in sawing and the quality of appearance. As the conventional examples, in the Patent Publication No. Hei 2-28073 and so on such details are disclosed. Further, a wood drying apparatus, in which the blast of a hot air in a treatment chamber is discussed and the efficiency is increased is disclosed in the Patent laid-open No. Hei 4-148484.
However, in the conventional wood treatment method and the apparatus thereof the following problems have been mentioned. As described above, in the method where any green wood is treated by adding artificial treatment, such as exposing the green woods to the hot blast and drying the woods, the change of the nature of the woods is carried out to prevent the woods from generating the ex post facto cracking or bending.
However, the nature-changed-status of the woods treated in the high temperature will destroy the balance of the internal stress when returning again to the normal temperature, and during the time process from a high temperature to a normal temperature, a cracking generation has been invited. Actually, the generation of cracking is apt to be experienced in 80% of the woods within one to two weeks after taking out from a treatment chamber and leaving as it is in the outer atmosphere. Thus, a technique for accelerating the nature change of the wood in order to increase the nature as lumber for building use and deriving the stable supply and the cost reduction of lumbers is not sufficient yet, and a further improvement for treating woods efficiently has been expected.